Pesticides - Re-entry Time

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What is a "re-entry time"?

The re-entry time (RET) (or re-entry period) is the minimum amount of time that must pass between the time a pesticide was applied to an area or crop and the time that people can go into that area without protective clothing and equipment.

NOTE: The term "pesticide" describes a very large and diverse group of chemicals or products. It is very important to always get specific information about the exact product you are using.

For more information, other OSH Answers documents in this series include:

Why are "re-entry times" important?

Re-entry times are set to protect people (and animals, for example in a kennel) against poisoning by pesticides if they enter a treated area too soon after application without proper protective equipment.

There are many ways a person can come in contact with a pesticide. In general, exposure to pesticides after they have been applied to their target may occur by:

Inhalation to vapours, dusts or mists

Skin contact of residues

Eye exposure to vapours, dusts or mists, or by rubbing your eyes with your hand, a glove or clothing that is contaminated with pesticide residue

Ingestion (eating food that has been treated or eating without first washing hands)

When treated plants are touched during work activities such as weeding, thinning, or brushing against plants, some pesticide may be transferred to skin. Workers in a field can also cause residues on plants and on the soil surface to "fly up" as a dust - the dust settles on the worker's skin and/or are inhaled. People in treated areas may also breathe fumes (vapours) from a recent pesticide application.

Sometimes it's not as easy to avoid residues as you might think. Be aware of spraying that neighbouring properties may be doing. On windy days, spray drift can travel a surprising distance. If you smell a "solvent" smell and/or you notice a residue on the leaves of the plants you are handling, leave the area and ask the grower if he or she has sprayed recently, and if necessary, ask neighbouring growers as well.

Where do I find re-entry times?

The label on the pesticide container provides information on the re-entry times. A pesticide container label consists of several panels of information. If all the information will not fit on these container panels then this extra information may be found in a separate booklet. There could also be stickers, tags, seals, leaflets, brochures and wrappers on, or attached to a container. For more information, please see the OSH Answers Pesticide - Labels.

Provincial re-entry guidelines may also be available. For example, the British Columbia Workers' Compensation Board Regulations for Occupational Health and Safety state that the minimum re-entry or restricted entry interval for:

a slightly toxic pesticide is 24 hours and

a moderately or very toxic pesticide is 48 hours.

Signs should also be posted that indicate spraying has occurred and what the re-entry time is.

Are re-entry times the same?

No. Different pesticides will have different re-entry times (RETs). Each pesticide may have one or more different RETs. Re-entry times are established by the following factors:

The toxicity of the active ingredient (actual poison) of the pesticide

If it is a mixture, what remains in the residue after application

How it is formulated (including adjuvants) - for example, organic solvents in pesticide formulations may increase the skin toxicity of some insecticides

If the pesticides are converted into more toxic compounds under certain environmental conditions

The rate and method of application including whether it is applied outdoors or in a confined space (such as greenhouses or barns)

Characteristics of the plant being sprayed (type of crop, height of crop at maturity, density of leaves, and how the plant will be handled, how close the pesticide is applied to harvest). Since different rates are used for each crop, the RET can vary between crops. For example, the RET for raspberries could be 7 days while the RET for apples could be 14 days.

Weather conditions may change how the pesticide is deposited (such as variations in temperature, sunshine, moistness and wind). For example, organophosphates and carbamates in hot and dry climates take longer to break down and longer re-entry intervals (1-2 weeks) are sometimes necessary to prevent acute poisoning of field workers.

The type of work being done after the pesticide is applied. Human contact with treated plants can vary. For example, a RET could be 14 days for thinning, but only 48 hours for irrigating.

How do you know if you have been exposed?

Recognizing symptoms of poisoning helps you to know to leave the area immediately and to begin first aid treatment if required. For a list of health effects, please see the OSH Answers document Pesticides - Health Effects.

Some poisoning symptoms can be vague and be confused with other illnesses such as flu, excess heat, or food poisoning. Be aware that acute pesticide poisoning symptoms may appear within a few minutes of exposure or may not be evident for hours. Use the "buddy system" and keep an eye on your co-workers as well. If anyone is acting or feeling unusual, or showing signs of poisoning, see a doctor and call your local Poison Control Centre:

If you notice symptoms in yourself or a co-worker:

Leave the area immediately. Find out what pesticide had been applied.

Get medical help. Take any information you have about the pesticide (e.g., bring the label or can) to the doctor or hospital.

If exposure happens on the job, report your condition to your supervisor immediately.

Thoroughly wash any exposed areas with soap and water, especially hands including under fingernails.

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